The following is the implementation of a simple text editor that is extended from the previous examples in its building version. This code contains some new features, such as QFontDialog, QFileDialog, and so on, which are discussed in Chapter 5, Dialogs and Widgets. Otherwise, the following code is self explanatory:
# Import required modules
import sys, time
from PySide.QtGui import *
# Our main window class
class MainWindow(QMainWindow):
# Constructor function
def __init__(self, fileName=None):
super(MainWindow,self).__init__()
self.initGUI()
def initGUI(self):
self.setWindowTitle("A Simple Text Editor")
self.setWindowIcon(QIcon('appicon.png'))
self.setGeometry(100, 100, 800, 600)
self.textEdit = QTextEdit()
self.setCentralWidget(self.textEdit)
self.fileName = None
self.filters = "Text files (*.txt)"
self.SetupComponents()
self.show()
# Function to setup status bar, central widget, menu bar, tool bar
def SetupComponents(self):
self.myStatusBar = QStatusBar()
self.setStatusBar(self.myStatusBar)
self.myStatusBar.showMessage('Ready', 10000)
self.CreateActions()
self.CreateMenus()
self.CreateToolBar()
self.fileMenu.addAction(self.newAction)
self.fileMenu.addAction(self.openAction)
self.fileMenu.addAction(self.saveAction)
self.fileMenu.addSeparator()
self.fileMenu.addAction(self.exitAction)
self.editMenu.addAction(self.cutAction)
self.editMenu.addAction(self.copyAction)
self.editMenu.addAction(self.pasteAction)
self.editMenu.addSeparator()
self.editMenu.addAction(self.undoAction)
self.editMenu.addAction(self.redoAction)
self.editMenu.addSeparator()
self.editMenu.addAction(self.selectAllAction)
self.formatMenu.addAction(self.fontAction)
self.helpMenu.addAction(self.aboutAction)
self.helpMenu.addSeparator()
self.helpMenu.addAction(self.aboutQtAction)
self.mainToolBar.addAction(self.newAction)
self.mainToolBar.addAction(self.openAction)
self.mainToolBar.addAction(self.saveAction)
self.mainToolBar.addSeparator()
self.mainToolBar.addAction(self.cutAction)
self.mainToolBar.addAction(self.copyAction)
self.mainToolBar.addAction(self.pasteAction)
self.mainToolBar.addSeparator()
self.mainToolBar.addAction(self.undoAction)
self.mainToolBar.addAction(self.redoAction)
# Slots called when the menu actions are triggered
def newFile(self):
response = self.msgApp("Confirmation","Do you like to save the current file?")
if response == "Y":
self.saveFile()
self.textEdit.setText('')
self.fileName = None
def openFile(self):
response = self.msgApp("Confirmation","Do you like to save the current file?")
if response == "Y":
self.saveFile()
self.fileName, self.filterName = QFileDialog.getOpenFileName(self)
self.textEdit.setText(open(self.fileName).read())
def saveFile(self):
if self.fileName == None or self.fileName == '':
self.fileName, self.filterName = QFileDialog.getSaveFileName(self, filter=self.filters)
if(self.fileName != ''):
file = open(self.fileName, 'w')
file.write(self.textEdit.toPlainText())
self.statusBar().showMessage("File saved", 2000)
def exitFile(self):
response = self.msgApp("Confirmation","This will quit the application. Do you want to Continue?")
if response == "Y":
myApp.quit()
else:
pass
# Function to show Diaglog box with provided Title and Message
def msgApp(self,title,msg):
userInfo = QMessageBox.question(self,title,msg,
QMessageBox.Yes | QMessageBox.No)
if userInfo == QMessageBox.Yes:
return "Y"
if userInfo == QMessageBox.No:
return "N"
self.close()
def fontChange(self):
(font, ok) = QFontDialog.getFont(QFont("Helvetica [Cronyx]", 10), self)
if ok:
self.textEdit.setCurrentFont(font)
def aboutHelp(self):
QMessageBox.about(self, "About Simple Text Editor",
"A Simple Text Editor where you can edit and save files")
# Function to create actions for menus
def CreateActions(self):
self.newAction = QAction( QIcon('new.png'), '&New',
self, shortcut=QKeySequence.New,
statusTip="Create a New File",
triggered=self.newFile)
self.openAction = QAction( QIcon('open.png'), 'O&pen',
self, shortcut=QKeySequence.Open,
statusTip="Open an existing file",
triggered=self.openFile)
self.saveAction = QAction( QIcon('save.png'), '&Save',
self, shortcut=QKeySequence.Save,
statusTip="Save the current file to disk",
triggered=self.saveFile)
self.exitAction = QAction( QIcon('exit.png'), 'E&xit',
self, shortcut="Ctrl+Q",
statusTip="Exit the Application",
triggered=self.exitFile)
self.cutAction = QAction( QIcon('cut.png'), 'C&ut',
self, shortcut=QKeySequence.Cut,
statusTip="Cut the current selection to clipboard",
triggered=self.textEdit.cut)
self.copyAction = QAction( QIcon('copy.png'), 'C&opy',
self, shortcut=QKeySequence.Copy,
statusTip="Copy the current selection to clipboard",
triggered=self.textEdit.copy)
self.pasteAction = QAction( QIcon('paste.png'), '&Paste',
self, shortcut=QKeySequence.Paste,
statusTip="Paste the clipboard's content in current location",
triggered=self.textEdit.paste)
self.selectAllAction = QAction( QIcon('selectAll.png'), 'Select All',
self, statusTip="Select All",
triggered=self.textEdit.selectAll)
self.redoAction = QAction( QIcon('redo.png'),'Redo', self,
shortcut=QKeySequence.Redo,
statusTip="Redo previous action",
triggered=self.textEdit.redo)
self.undoAction = QAction( QIcon('undo.png'),'Undo', self,
shortcut=QKeySequence.Undo,
statusTip="Undo previous action",
triggered=self.textEdit.undo)
self.fontAction = QAction( 'F&ont', self,
statusTip = "Modify font properties",
triggered = self.fontChange)
self.aboutAction = QAction( QIcon('about.png'), 'A&bout',
self, statusTip="Displays info about text editor",
triggered=self.aboutHelp)
self.aboutQtAction = QAction("About &Qt", self,
statusTip="Show the Qt library's About box",
triggered=qApp.aboutQt)
# Actual menu bar item creation
def CreateMenus(self):
self.fileMenu = self.menuBar().addMenu("&File")
self.editMenu = self.menuBar().addMenu("&Edit")
self.formatMenu = self.menuBar().addMenu("F&ormat")
self.helpMenu = self.menuBar().addMenu("&Help")
def CreateToolBar(self):
self.mainToolBar = self.addToolBar('Main')
if __name__ == '__main__':
# Exception Handling
try:
myApp = QApplication(sys.argv)
mainWindow = MainWindow()
myApp.exec_()
sys.exit(0)
except NameError:
print("Name Error:", sys.exc_info()[1])
except SystemExit:
print("Closing Window...")
except Exception:
print(sys.exc_info()[1])The sample output of the preceding program is given in the following screenshot:
The preceding example is a very simple text editor performing some basic functions. We will build upon this example in the coming chapters, as and when we discuss some new features.
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